1. Field of the Invention
The invention relates to an input device for mobile, and particularly portable digital computers, and to a portable digital computer with input device.
2. Description of Related Art
Portable digital computers have recently become widely used. These portable digital computers include, in particular, the so-called notebooks, by which two-leaf portable digital computers are meant in which a lid part containing a display device and a base part provided with a keyboard are moveably coupled with one another by means of a hinge device so that they can be opened and shut like a book. Apart from this, there are, in particular, so-called Tablet PC computers which are constructed to be single-leafed. Finally, a large variety of portable digital computers constructed as mini devices have conquered the markets in the form of so-called personal digital assistants (PDA).
In this context, so-called e-book readers must not be forgotten which frequently also utilize mouse functions. Such technologies have been described, in particular, in the earlier printed documents International Patent Application Publications WO 2001073673 A2 and WO 1999015982 A1; the content of these printed documents is expressly incorporated by reference herein.
Portable devices are always also meant to be “mobile” devices in the sense of the present patent. This also includes devices which can be used in means of transport such as motor vehicles.
The numerous situations of application in connection with the practical use of these portable digital computers outlined above that is required that the user can move and position a pointer, commonly called “cursor”, on the screen of the display device by means of a suitable input device. The traditional aid for this is the so-called “mouse”. A mouse is a moveable input device which enables the user to position and/or to select objects shown on the display device in interaction with an operating system and other software. Such a mouse is known, for example, from the document U.S. Pat. No. 5,805,144.
A mouse typically consists of a sliding part which can be gripped by the user with the fingers of one hand or also with a flat hand and pushed to and fro on a level surface, for example a table surface. A sensor device provided in the sliding part detects the movement of the mouse in accordance with path length and path direction relative to the surface on which the mouse is moved, and conveys these movement quantities in a suitable manner with a digital computer via a cable link. The digital computer then interprets these movement quantities by processing certain data processing programs which are usually components of the operating system and/or of application programs. Typical mouse-controlled functionalities are the following:                1. Selecting functions by positioning the mouse pointer on the display device in a screen area which, in accordance with suitable conventions, is considered by the user as a graphic symbolization of a function.        2. Actuating functions, i.e. single or rapidly successive double-activation of a mouse key when the mouse pointer is located over a screen area which, in accordance with suitable conventions, is considered by the user as a “button” on the display device;        3. Marking information items between a first position on the screen and a second position on the screen within the framework of a predetermined geometric model, i.e. positioning the mouse pointer on the display device at a first position, then operating and keeping a mouse key operated and then, whilst keeping the mouse key operated, moving the mouse pointer to a second position, finally releasing the mouse key, wherein the geometric model can be, for example, a rectangle, a linear arrangement, an ellipse or the like;        4. Scrolling functions;        5. Inserting selection information such as, for example, context menus.The above list of functions is only intended to be by way of example; the context of this patent specification also includes all functions possible by means of a mouse pointer.        
Almost all programs which have a graphical user interface provide the user at least optionally with the possibility of performing the entire navigation in the program functions by means of a mouse or equivalent input devices. Examples of this are the navigational concept of the “Windows” operating system software by Microsoft or the navigational concept of the user interface “KDE” for computers which are operated under the Linux operating system. The expert knows these user interfaces and no further explanation will therefore be provided here.
Mice in which a roller ball arranged on the underside of the sliding part and freely rotatably rolls along on the support on which the mouse is moved are in widespread use, the relative motion between roller ball and sliding part housing produced as a result being detected in a suitable manner, for example by means of measuring rollers and converted into an electrical signal. Since the roller ball is mechanically sensitive and, moreover, is susceptible to soiling, there are also attempts to detect the motion of the sliding part over the surface on which the mouse is pushed, contactlessly optically in that optically detect able surface patterns present in any case or arranged on a mouse support are detected by optical sensing means and converted into motion signals.
In principle, mice provided with a roller ball can also be used in an alternative mode in which the housing is located stationary on a support, for example a table top, the roller balls being rotated with fingers or at the ball of the thumb of one hand of the user. Mouse devices optimized for this operating mode are also called “trackball”.
It is usually found to be expedient to provide mice or, respectively, trackball devices, with keys, adjusting wheels and other operating elements at a suitable place on the housing in order to be able to carry out, for example, complete selection processes in a simple and clearly understood manner by the user.
In the practical use of portable digital computers, mice and trackball devices provided with cables have always been found to be unwieldy in as much as the user, in addition to the actual digital computer, must also carry the mouse or the trackball device, respectively, as a further object. A mouse or trackball device, respectively, provided with a sufficiently long cable presents problems since, on the one hand, the cable must be wound up before being transported or secured in another manner against being twisted and, on the other hand, requires a corresponding unwinding process before being used. During operation, the cable can become caught on other objects located in the vicinity and present discomfort and inconvenience to the user. To deal with these problems, so-called “cableless” mice or trackball devices are known in which the motion data of the sliding part are transferred to the digital computer wirelessly via a short-range radio link or by infrared data transmission.
For the user of a portable digital computer, however, the use of such a cableless mouse or of a cableless trackball device means that he has to carry along three parts, namely the portable digital computer, a base station provided with a short cable stub for connection to the digital computer, and the sliding or trackball part. In practice, it has been found to be problematic always having to pack up and reliably carry along all three parts during the transport.
The power supply represents a further problem because either sufficient batteries must be kept in stock which can rapidly become discharged due to frequent use and thus have to be frequently replaced, or a charging device must be carried along as a further component in the case of a rechargeable battery.
An approach at remedying these problems, known from the prior art, consists in dispensing completely with the mouse or the trackball device as an independent part and instead installing a sensor for transmitting location and displacement data directly into the portable digital computer. A widely used exemplary embodiment of this approach is the so-called “slide pad”. A “slide pad” is a small area with sides of a few centimeters' length which is equipped with suitable sensors in such a manner that during a sliding contact with a fingertip moving on the area, a signal representing the motion path and motion direction can be detected and processed further by the digital computer. Solutions are also known in which a pin slightly protruding from the keyboard plane is arranged in the keyboard which can be bent in one direction via the full force acting on it with a fingertip. This action of the force is measured by suitable sensors and transmitted as motion direction and motion length signal to the digital computer. Finally, solutions are known in which a trackball device is permanently installed in the portable digital computer.
Although these approaches at improvement considerably simplify the transport problem for the user since now only a single part, namely the portable digital computer must be packed up and transported; according to experience, however, the ergonomic characteristics of such permanently installed mouse substitutes considerably lag behind those of an external mouse or of an external trackball device, respectively, because of the close proximity to the keyboard and due to the mechanical housing dimensions which are always kept small.
From U.S. Pat. No. 5,126,955, a notebook is known which exhibits a scanner mouse unit connected by means of a cable. It is only intended to store the scanner mouse part in the storage part for purposes of transport. There is no mouse functionality in the storage part of the keyboard. The cable restricts the freedom of motion and limits the possibilities. A roller ball is used for the mouse function.
From U.S. Pat. No. 5,049,863, a keyboard unit is known which, although it can be applied with PCs and notebooks and specifies an infrared connection instead of a cable connection, a part-keyboard segment is used for it in order to create, due to a possibility of decoupling the key segment, a mouse which generates mouse signals via a roller ball. On the top, the removed keyboard segment is only equipped with the cursor keys of the keyboard which does not offer a functionally equivalent alternative to an integrated notebook mouse due to its arrangement and its restricted usefulness. An integrated mouse would have to be constructed in addition. Moreover, the removable key unit is fed with a non-rechargeable dry battery which would have to be replaced more frequently, especially with more intensive use. In this context, it is very disadvantageous always to have to keep spare batteries in stock. A further disadvantage is the infrared link which can also restrict the freedom of movement. Moreover, it is disadvantageously provided expressly that when the keyboard segment is inserted into the keyboard, it operates a switch which switches off the power supply for the keyboard segment.
From U.S. Pat. No. 5,546,334, a decoupleable keyboard and a decoupleable integrated trackball mouse is known which, however, are only to be decoupled for repair purposes or when the notebook is to be used without trackball. Neither the keyboard nor the trackball mouse are electrically connected to the notebook and functionally operable after the mechanical decoupling.
From U.S. Pat. No. 5,726,684, a notebook with a decoupleable integrated mouse with trackball is known, wherein these can be operated both by cable, infrared or radio. For this purpose, the decoupled mouse, after removal from the notebook housing is turned over so that the roller ball can generate mouse signals by being moved over a level surface. Here, too, a non-rechargeable dry battery is provided which must be replaced after having been used up.
From printed document U.S. Pat. No. 6,476,795 A, a notebook is known by means of which it is possible to charge up radio mice. However, this is done in a complex manner with the aid of a module to be inserted for this purpose into a drive bay of the notebook, for example for inserting a CD ROM drive. In this arrangement, a radio mouse can be charged up via an intermediate battery in the auxiliary module. It is intended, however, to charge up conventional radio mice. The solution shown does not have the aim of decoupling an integrated mouse so that it can also be used as external mouse. Instead, the mouse must be transported and stored as second external mouse. The charging module can remain in the notebook but this blocks the coupling interface for modules which may be more important. Any permanent integration of the module would, therefore, be rather disadvantageous for space and cost reasons.
From U.S. Patent Application Publication 2001/0033267 A1, a notebook having a number of coupling possibilities for function modules such as an external infrared mouse is known which can be wirelessly effectively connected to the notebook. However, this is shown as additional possibility to a permanently integrated mouse. The notebook mouse cannot be removed from the notebook. The solution is based on the placement of IR transmitters at various points on the notebook in order to increase the freedom of movement with a radio mouse shown externally. The charging up of a coupleable mouse module is not shown.